Dietary Fat and Disease
A topic of great concern in modern nutritional medicine, which will be discussed throughout this book, is the correlation between increased dietary fat intake and disease. Research continues regarding the relationship between disease and cholesterol and the types of fats consumed. We now know that two aspects of diet must be considered: first, the total amount of fat intake—that is, the percentage of the total diet consisting of fats and oils, both saturated and unsaturated fats (mono- or polyunsaturated), and second, the types of fats consumed. Saturated and hydrogenated fats seem to be worse in regard to increasing cholesterol and causing vascular congestive problems than the vegetable-source unsaturated ones, which may actually improve cholesterol by reducing the LDL:HDL ratio and decreasing total cholesterol. Fried foods seem to be more difficult for the body to process, as well.

Of the diseases related to increased fat intake, number one is atherosclerosis. Clogging, or atherosclerosis, of the coronary arteries (the blood vessels that nourish the heart muscle itself with blood) is the disease process causing the most deaths in the Western “affluent diet” cultures. Clogging vital arteries with plaque (consisting of fat, mucopolysaccharides, calcium, platelets, and smooth muscle cells) decreases the delivery of life-supporting blood to the tissues and is related to a variety of other diseases. Narrowing and stiffness of the blood vessel resulting from arterial plaque leads to high blood pressure, or hypertension, which forces the heart to work harder to get the blood to the body. This constant extra effort can lead to enlargement of the heart, general heart disease, and congestive heart failure. Coronary artery disease leads to the physical limitations associated with angina pectoris and is the primary cause for the big business of coronary artery bypass surgery.

Two major types of cancer are associated with excessive dietary fat intake. The first one is the most common cancer in men and women combined, cancer of the colon and rectum. The other is the most common major female cancer, cancer of the breast. Both of these can be deadly, especially if they are not diagnosed early, and both are associated with a high-fat, low-fiber diet. There is also an association between prostate cancer in men and uterine and ovarian cancer in women and high dietary fat consumption, particularly saturated fats found in animal foods.

Obesity is much more likely in people who eat a high-fat diet, which is often a high-calorie diet, since each gram of fat contains nine calories instead of the four calories in each gram of protein or carbohydrate. With obesity comes an increased risk of all the previously mentioned diseases, such as atherosclerosis, hypertension, and certain cancers, besides a variety of other problems, including adult-onset diabetes.

I want to further delineate the role of fats in cardiovascular diseases. Saturated fats and hydrogenated vegetable oils, which contain high amounts of saturated fats in place of their once polyunsaturated oils, both raise serum cholesterol. The liver makes cholesterol from saturated fats. A number of factors can increase the risk of cardiovascular disease. The top three are elevated serum cholesterol, smoking, and high blood pressure. (For cholesterol, the most important factor is elevated LDL.) Anyone who smokes, has high blood pressure, and has a serum cholesterol level of more than 250, especially with a high LDL:HDL ratio, is almost certain to close off his or her arteries relatively rapidly. Other risk factors for the cardiovascular diseases include stress, obesity, gender (the female hormone estrogen is protective for women), heredity (for heart disease or for higher cholesterol levels), lack of exercise, and elevated blood triglyceride levels. We are in a position to reduce most of these risk factors by changing our lifestyles and dietary habits, and doing so will significantly reduce our chances of developing blood vessel and heart disease. Overall, the best way to lower risks of cardiovascular disease is to reduce total and saturated fat intake, keep the blood pressure normal, not smoke, and exercise regularly.

The current theory about the body’s process of forming plaque in the arteries is rather complex. A simple version is as follows: The liver produces cholesterol mainly from the saturated fats. The LDLs are the primary carriers of cholesterol through the blood and to the plaques, so the higher the intake of saturated fats (increasing cholesterol and LDLs), the greater the potential for plaque formation. The smooth muscle cells in the middle layer of the arterial wall invade the inner wall to help form the plaques, which start from some irritation of the inner lining that may come from irritants such as smoking, viruses, chemicals in the diet, and increased stress. High blood pressure also causes increased stress on the artery walls. These irritations attract platelets and LDL cholesterols and thicken the wall with plaque. HDLs carry cholesterol away from plaque and out of the bloodstream back to the liver for reprocessing, so higher HDL levels reduce the likelihood of plaque formation.

An important key to preventing cardiovascular disease is lowering serum cholesterol and LDL levels and raising the HDL cholesterol in ratio to the total cholesterol and to LDL. This can be done by following my repeated suggestion, which is also that of the government and the American Heart Association: lower intake of saturated fats found in meats and animal foods, in milk products, and in hydrogenated oils and increase the proportion of mono- and polyunsaturated vegetable-source fats and oils in the diet. In general, a fat-modified diet can lower serum cholesterol from 20–40 percent, especially if exercise is included. Polyunsaturated fats specifically can lower cholesterol by reducing lipoprotein (LDL) synthesis and increasing lipoprotein breakdown, as well as by the effect of the essential fatty acid linolenic acid. Linolenic acid reduces plaque formation and thrombosis by decreasing platelet aggregation, promoting prostaglandin (E3 series) synthesis (which also influences platelets), and decreasing LDLs. The essential fatty acids also influence the intravascular coagulation as well as energy metabolism within the myocardial muscle of the heart.

One of the main ways to raise HDL levels is exercise—that is, regular, prolonged, aerobic-type exercise. Females normally have higher levels of HDL and thus a reduced cardiovascular disease risk. Smoking lowers HDL, so stopping smoking will help raise it, besides reducing the increased risk caused by the vascular irritation of smoking. Also, the polyunsaturated fat level influences the HDL level, and the omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) found in fish, help to raise HDL levels and reduce the risk of cardiovascular disease.

Factors that help lower LDL levels, besides reducing saturated fat and dietary cholesterol, include eating a relatively higher amount of mono- and polyunsaturated fats compared to the saturated or hydrogenated varieties; adding specific nutrients, such as sufficient dietary vitamin C (a deficiency of vitamin C can raise LDL); avoiding excess copper, sodium, and iron intakes, which can raise LDL; and getting sufficient chromium and natural dietary fluoride, as deficiencies can raise LDL. A diet high in animal protein can raise LDL, whereas eating a higher percentage of vegetable protein helps to lower it. Sufficient fiber in the diet, particularly from the legumes, vegetables, and fruits (such as apples that contain pectin), helps in lowering LDL as well.

With regard to nutrition and cancer (our second most prevalent deadly adult disease), it is likely that more than 50 percent (probably more) of cancer occurrences are related at least in part to diet. The Hunza tribes of Pakistan who are known for their longevity and have the lowest known cancer rates eat an exclusively natural, chemical-free diet of foods they grow themselves. High animal protein intake and low dietary fiber consumption are two important factors increasing cancer incidence, but the one that is being shown to be the most significant is increasingly high intake of fats, particularly the saturated animal fats, in the diet. Many chemicals in foods, used as preservatives or from herbicides and pesticides, may be carcinogenic in the body, especially in the gastrointestinal tract, and many of these chemicals are stored in animal fats. Artificial red dyes, cyclamate, nitrites and nitrates in processed meats, and saccharin have all been implicated in cancer.

The theory of how fat can cause cancer in the colon and rectum is based on the fact that fats in the diet cause release of bile acids from the gallbladder and liver into the intestine to help emulsify the fats. High-fat diets stimulate increased bile acid levels in the colon. Fat in the diet also weakens the metabolism of the normal colon bacteria which, when functioning optimally, may help protect the colon lining from carcinogens. These altered microflora interact with the bile acids to potentially create compounds that may cause cancer. An increased fiber content, even in a higher-fat diet, seems to be protective by increasing bowel motility, by diluting these carcinogenic substances through its bulking action, and by improving bacterial detoxification functions.

More than 100,000 new cases of cancer of the colon are diagnosed each year. The high-fat diet increases the incidence of this cancer, which, if diagnosed early, can usually be cured through major surgery, a drastic measure that could be prevented. The high-fat diet is also commonly associated with a higher fried-food component and lower fiber content, two other important dietary factors in carcinogenesis in the colon.

Numerous studies have shown the relationship of dietary fat to colon cancer. Research with the Seventh-Day Adventists who eat a vegetarian diet reveals that their incidence of colon cancer is much lower than average. They usually consume a diet higher in fiber and lower in fat than the average American. A study of the Mormon high-fiber diet has more clearly isolated dietary fats as the main connection to colon cancer incidence. Other nutritional qualities of the fruit and vegetable fiber foods seem to help inhibit cancer formation as well. Vitamins C and E, beta-carotene, and selenium, plus the plant sterols and antioxidant phenolic compounds like bioflavonoids from foods such as berries and citrus fruits, all seem to be beneficial factors. The cruciferous vegetables, such as broccoli and cabbage, seem to have other factors such as sulfhydryl-containing molecules besides the fiber that may protect against the development of cancer.

Cancer of the breast and a high-fat diet have been shown to be related for some time. It is thought that saturated fats generate more cholesterol and higher estrogen levels in women. This theory supports the dietary fat and breast cancer relationship as estrogen is particularly related to increased incidence of female breast cancer. Although the dietary fat and breast cancer question is not conclusively answered, it is generally agreed that, in regards to this disease, a low-fat, high-complex-carbohydrate diet minimizing alcohol, cigarettes, and preserved and chemical foods is still the best way to live to help prevent breast cancer. Countries, such as Japan, whose people traditionally eat a low-fat diet have a much lower incidence of breast cancer than countries eating higher quantities of animal fat, such as the United States, Australia, New Zealand, and the countries of Western Europe. Japanese who eat more Westernized diets in their own country or who move to a country eating a Western diet have a higher incidence of breast cancer. In the United States, Seventh-Day Adventist women on a vegetarian diet exhibit a lower incidence of this disease.

Not all recent studies correlate higher cancer incidence solely with total fat intake. There is some question as to whether certain fats are more significant than others. Milk fat and dairy foods have been implicated in several studies. The strongest correlation for breast cancer has been with the intake of the trans-fatty acids that are created when vegetable oils are hydrogenated to make margarine and solid vegetable shortening. There is even some concern with the polyunsaturated fats. Since they are less stable, they can go through peroxidation, which can lead to the formation of epoxides that may be cancer causing. This is especially true when these fats are heated. (Vitamin E and beta-carotene are two antioxidants which protect against the peroxidation process.) Because of this, I suggest using polyunsaturates moderately, along with some monosaturates, such as olive oil, which are more stable, while cutting down on the saturated fats.